Trapezoid Calculator

Trapezoid Calculator

Find trapezoid area from the two bases and height, and verify perimeter when both legs are known.

Last updated: June 2026 | By Patchworkr Team

Trapezoid Geometry Solver

Base A is required.

Area uses the average of the two parallel bases times the height. Perimeter is shown only when both legs are supplied and the measurements are geometrically consistent.
Live Results
Area
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Perimeter
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Formulas

Area: A = ((a + b) / 2) x h

Perimeter: P = a + b + c + d

For a valid trapezoid, the two leg lengths and height must be consistent with the base difference. This calculator checks that relationship before reporting perimeter.

Worked Example

Example: bases 8 and 16, height 3, legs 5 and 5

Input: a = 8, b = 16, h = 3, c = 5, d = 5
Area: ((8 + 16) / 2) x 3 = 12 x 3 = 36
Perimeter: 8 + 16 + 5 + 5 = 34
Geometry check: sqrt(5^2 - 3^2) + sqrt(5^2 - 3^2) = 4 + 4 = 8 = |16 - 8|
The calculator will display area 36 and perimeter 34 for this valid isosceles trapezoid.

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